Northerly geographical range extensions or changes in the geographical distribution of fish populations have been recently documented for European Continental shelf seas and along the European Continental shelf edge. These geographical movements have been related to regional climate warming and are predominantly associated with the northerly geographical movement of fish species with more southern biogeographical affinities. These include the movement of sardines and anchovies northward in the North Sea and red mullet and bass extending their ranges northward to western Norway. New records were also observed over the last decade for a number of Mediterranean and north-west African species on the south coast of Portugal. The cooling and the freshening of the north-west Atlantic over the last decade has had an opposite effect, with some groundfish species moving further south in their geographical distribution.

Regional climate warming in the North Sea has affected cod recruitment via changes at the base of the food web. Cod, like many other fish species, are highly dependent on the availability of planktonic food during their pelagic larval stages. Key changes in the planktonic assemblage caused by the warming of the North Sea over the last few decades has resulted in a poor food environment for cod larvae and hence eventual recruitment success. This research is an example of how both the dual pressures of over-fishing and regional climate warming have conspired together to negatively impact a commercially important fishery. Recent work on pelagic phenology has shown that plankton communities, including fish larvae, are very sensitive to regional climate warming with the response to warming varying between trophic levels and functional groups. These changes, again seen in the North Sea, have the potential to be of detriment to commercial fish stocks via trophic mismatch. The ability and speed in which fish and planktonic communities adapt to regional climate warming is not yet known.